My early thoughts on this is that Steve is being insufferable and I'm not sure why Kayla is putting up with it.

They walked a very fine line with making Kayla determined, but not a doormat. In this section, they get a little too close to the doormat side. But that does get balanced out in the aftermath - particularly when Jack first shows up in town.

Oh, so Jack hasn't arrived at this point? Why is Jo being so cagey about Billy, then? I thought she met Harper and he threatened her into keeping quiet?

Well, I don't know exactly where you are, but Jack shows up after Adrienne remembers and gets Steve out of the charges. And I think Jo is being cagey because they are setting the anvils for Jack's arrival. The Harper thing was a retcon that makes no sense with anything surrounding Jack's initial arrival.